Crop Varieties Research Articles

Factors influencing urban farmers’ intention to adapt to climate change in Addis Ababa, Ethiopia: a protection motivation theory

Globally, climate change (CC) is a widely recognized fact, particularly in the past few decades. Developing nations like Ethiopia have been experiencing climate change and its effects on agriculture. In this regard, urban agriculture is one of the sectors significantly impacted by adverse change in climate. However, there is scant empirical evidence on the factors influencing urban farmers’ intention to adapt to climate change in urban centers of Ethiopia. To fill the research gap, this study aimed to identify factors influencing urban farmers’ intention to adapt to climate change in Addis Ababa, Ethiopia. In doing so, a quantitative research approach with a random sampling technique was applied. Based on the protection motivation theory (PMT), primary data were collected from 364 respondents using a survey questionnaire. Accordingly, structural equation modeling (SEM) was used to identify and analyze the underlying relationships among the nine constructs used in this study. Hence, the results revealed that selecting new crop varieties, water management practices, adjusting dates of sowing crops with changing local climatic conditions, and sowing drought-resistant crops were major adaptation practices. Hence, the perception of CC indicators, the perceived effects of CC, incentives, subjective norms, adaptation efficacy, and self-efficacy were found to positively and significantly influence urban farmers’ intention to adapt. In contrast, urban farmers (UFs) show less intention to adapt to CC when subjected to maladaptive behaviors. Based on this, the study recommends strengthening the capacity of local institutions, farmer training and education, climate information dissemination such as early warning systems, access to extension services, and access to finance to equip urban farmers to undertake practical adaptation strategies in the face of climate change.

Genome-wide analysis of ascorbate peroxidase and functional characterization of SpAPX249b and SpAPX285c for salt tolerance in Sesuvium portulacastrum L.

We have identified 33 SpAPXs from S. portulacastrum genome and found SpAPX249b and SpAPX285c are important for halophyte salt tolerance. Ascorbate peroxidase (APX) is a vital antioxidant enzyme, involved in plant development and stress response by scavenging excessive reactive oxygen species (ROS). APX genes have been characterized in many plant species. However, their role in Sesuvium portulacastrum L. has not yet to be fully investigated. Here, we identified 33 SpAPXs from its genome and divided them into five subgroups across the 16 chromosomes. Cis-element analysis of their promoters indicated that all the detected SpAPXs showed potential roles in response to biotic and abiotic stresses as well as phytohormone effects on the plant growth and development. Transcriptomic data of the different tissues revealed that 9 SpAPX genes were specifically expressed in root and 13 ones were specifically expressed in leaves, with SpAPX249b prominently expressed in root and SpAPX285c in leaves. Moreover, quantitative real-time PCR analysis revealed that both SpAPX249b and SpAPX285c genes expressed only after NaCl application and were sharply induced in the high concentration of NaCl treatments. Our findings suggested that SpAPX249b and SpAPX285c may associate with plant salt tolerance and can serve as valuable genes for enhancing salt tolerance in other plants. By introducing these genes into other plants, it is possible to develop new varieties of salt-tolerant crops, thereby expanding the utilization of saline-alkali land and increasing agricultural productivity. In coastal saline-alkali wetlands, this halophyte can thrive in large numbers due to its inherent salt-tolerant genes, contributing to the restoration of polluted or ecologically degraded coastal saline-alkali wetlands.

Maximizing Crop Resilience: Exploring Stay-Green Traits for Sustainable Agriculture and Crop Research

The “stay-green” trait, distinguished by detained aging, sustain photosynthetic activity, nutrient use efficiency, offering critical advantages in drought, heat, and nutrient-deficient conditions. This review examines how "stay-green" traits can help crops better withstand the challenges of climate change, ensuring food security for a growing global population while conserving resources in the face of scarcity. This phenomenon is crucial in promoting yield stability, biomass production, and improved grain filling, thereby addressing the global demand for sustainable agriculture. This provides a detailed analysis of stay-green traits in various crops like maize, rice, wheat, barley, millets and fodder crops, emphasizing their genetic basis, physiological mechanisms, and practical applications like stay green trait enhance crop yield, drought and heat tolerance, nutrient use efficiency and resistance to abiotic stress by prolonging photosynthesis and delaying senescence. It explores into hormonal regulation, reactive oxygen species scavenging, and nutrient remobilization as underlying mechanisms. This paper also underscores advancements in phenotyping technologies and molecular breeding approaches, such as marker-assisted selection and CRISPR-Cas gene editing, for effectively incorporating stay-green traits into crop breeding programs. Real-world examples from cereals such as wheat, maize, and sorghum highlight the significant impact of stay-green traits on crop improvement. The potential of these traits is not limited to agricultural crops; they can also enhance the quality and marketability of horticultural produce. This review article focused on the emerging biotechnological tools, including nanotechnology and omics-based breeding, as future directions for enhancing stay-green traits and overall crop resilience. By integrating stay-green traits with broader stress tolerance strategies, this review advocates for a sustainable agricultural system that balances productivity and ecological conservation. The insights provided lay the groundwork for future research and innovation in developing resilient crop varieties to ensure climate variability presents concerns to global food security.

Enhancing drought tolerance in cumin through physiological and genetic insights from a synthetic variety

Developing drought-tolerant crop varieties is essential for sustainable agriculture and food security, particularly in arid and semi-arid regions. This study introduces a newly developed cumin variety (Cuminum cyminum L.), a high-value medicinal plant, bred for enhanced resilience against drought stress. The synthetic variety was evaluated over three growing seasons under normal irrigation (field capacity) and severe drought stress (30% of field capacity) conditions. Results indicated that the synthetic variety exhibited a 71.59% higher seed yield, 46.53% greater chlorophyll a content, 24.03% more total chlorophyll, and a 52.90% increase in proline accumulation under drought stress compared to parental genotypes. Under drought stress conditions, the enzymatic activity of catalase, peroxidase, and ascorbate peroxidase was 131.81%, 122.05%, and 264.78% higher, respectively, in the synthetic variety compared to the parental genotypes, contributing to its improved drought tolerance. Furthermore, the synthetic variety demonstrated a 95.02% increase in essential oil content and favorable shifts in essential oil composition under stress conditions. Molecular analysis using ISSR markers revealed significant genetic diversity with polymorphic percentages ranging from 66.67 to 100%. Clustering and principal coordinates analysis (PCoA) confirmed clear distinctions between the synthetic variety and its parental genotypes. These findings highlight the synthetic cumin variety as a promising candidate for sustainable agriculture in water-limited regions, combining drought tolerance with superior agricultural productivity.

Determinants of smallholder farmers’ choices of adaptation strategies to climate variability in the Ayehu watershed, Upper Blue Nile Basin, Ethiopia

ABSTRACT Adapting to climate variability is essential for sustainable livelihoods in developing countries like Ethiopia, where rainfed agriculture is vital. This study examines indigenous and introduced adaptation strategies across different agroecological zones, identifying the factors influencing their selection. Data were collected from 338 agricultural households using a questionnaire. The weighted average index (WAI) identified the main adaptation techniques, while the problem confrontation index (PCI) assessed barriers to effective adaptation. The multinomial logit model (MNL) analyzed the factors affecting adaptation choices. The results showed that indigenous methods like cultivating local crop varieties (WAI = 2.22), diversifying crops (WAI = 2.15), and adjusting planting dates (WAI = 2.14) were prevalent, while introduced strategies included using inorganic fertilizers (WAI = 2.64) and improved crop varieties (WAI = 2.41). Barriers such as limited farm size, lack of climate information, poor soil quality, and high input costs were identified through PCI. The MNL model highlighted education, access to credit, extension services, climate perception, and household income as key factors influencing adaptation strategies. These findings emphasize the need for region-specific interventions tailored to local environmental and socioeconomic conditions, which can help policymakers develop effective climate adaptation strategies that enhance resilience and sustainability in farming communities.

ZmDREB1A Regulates myo-Inositol-1-phosphate Synthase 2 Controlling Maize Germination at Low Temperatures.

Transcription factor DREB1A positively regulates plant chilling stress tolerance. However, its role in regulating seed germination at low temperatures has remained a mystery. Our research has unveiled that maize zmdreb1a mutant seeds exhibit decreased ZmMIPS2 expression and a lower germination percentage than the control under low temperatures. The overexpression of ZmDREB1A upregulated ZmMIPS2 expression, while the mutation of DRE motifs in the ZmMIPS2 promoter nullified the influence of ZmDREB1A on the target gene expression. In addition, we demonstrated that ZmDREB1A directly binds to the three DRE motifs in the promoter of ZmMIPS2 both in vitro and in vivo. Further investigation has shown that maize zmmips2 mutant seeds are more sensitive, while ZmMIPS2 overexpressing seeds are more tolerant of low temperatures during seed germination. These findings could be applied to develop new crop varieties that are more resilient to low temperatures during the vulnerable germination phase.

Exploring the plant microbiome: A pathway to climate-smart crops.

Exploring the plant microbiome: A pathway to climate-smart crops.

Field plants strategically regulate water uptake from different soil depths by spatiotemporally adjusting their radial root hydraulic conductivity.

Plants modify their root hydraulics to maintain water status and strategically use soil water, but how they achieve this in the field conditions remains elusive. We developed a method to measure and calculate daily root water uptake, root water potential, and radial root water permeability at different depths in a wheat (Triticum aestivum L.) field and a permanent grassland dominated by ryegrass (Lolium perenne L.). During the drying processes, both plant systems reduced the radial water permeability of their shallow roots to limit topsoil water uptake, while increasing the radial water permeability of their roots in the subsoil to enhance water extraction. Conversely, after the topsoil was rewetted, both plant systems increased the radial water permeability of their shallow roots to enhance water extraction, while reducing the radial water permeability of their roots in the subsoil to limit water uptake. Root water uptake in the subsoil was more influenced by the topsoil water than by the subsoil water. The topsoil water serves both as a resource and a signal, coordinating optimal water uptake from different soil depths. These findings have important implications for understanding how plants cope with periodic water stress in the field and for screening drought-tolerant crop varieties.

Responses of cereals to nitrogen deficiency: Adaptations on morphological, physiological, biochemical, hormonal and genetic basis

Nitrogen (N) is a primary macronutrient essential for plant growth and development. Global nitrogen fertilizer consumption is approximately 120 million tons, with nitrogen use efficiency (NUE) ranging between 25 % and 50 %. Excessive use of nitrogen fertilizer poses significant risks to the envi ronment and living organisms, highlighting the need to reduce fertilizer ap plication, improve NUE, and sustain crop productivity. Sustainable agricul tural practices emphasize minimizing fertilizer usage. Therefore, developing high-NUE crop varieties capable of maintaining yields under reduced nitro gen input is critical for ensuring food security and protecting ecosystem. A promising strategy involves investigating plant responses to varying nitro gen levels, particularly under low-nitrogen conditions. This review explores the morphological, physiological, biochemical, hormonal, and genetic changes in cereals subjected to low-nitrogen conditions. Morphological adaptations include alterations in root and shoot architecture, while physi ological responses involve enhanced chlorophyll content, leaf nitrogen lev els, and photosynthetic efficiency. Biochemical changes are characterized by increased activity of nitrogen uptake and assimilation enzymes, accom panied by hormonal shifts such as elevated auxin levels in roots. These traits provide a foundation for developing nitrogen-efficient crop varieties. Future research should prioritize breeding crops with enhanced tolerance to low-nitrogen conditions to improve NUE, grain quality, and yield potential.

Effect of thermal and non-thermal processing on fermentable oligo-di-monosaccharides and polyols (FODMAPs) content in millet, sorghum, soybean and sesame varieties

This study investigated the effect of processing (roasting and malting) and crop variety on fermentable oligo-di-monosaccharides and polyols (FODMAPs) profile of millet, sorghum, soybean, and sesame varieties commonly consumed in Uganda. Two elite varieties and one indigenous variety for each crop were analyzed. Monosaccharide and polyols content was determined by HPLC-UV method, while disaccharides and oligosaccharide were determined using Megazyme kits. The elite varieties of soybean (Maksoy 3 N), Millet (Seremi 2) and sorghum (Narosorg 2) exhibited significantly (p < 0.05) lower oligosaccharide content compared to indigenous varieties with percentage differences ranging from 10.2 to 73.9%. Additionally, Maksoy 3 N and Narosorg 2 also exhibited significantly lower (p < 0.05) excess fructose content compared to the indigenous variety. Malting was more effective than roasting (p < 0.05) in reducing FODMAP categories and total FODMAP content. Malting effectively reduced excess fructose in all grain types to the recommended levels of <0.15 g/100 g compared to roasting. Moreover, malting reduced total oligosaccharides and total FODMAPs in soybean and sesame by more than 50%. However, this reduction did not achieve the recommended threshold of 0.3 g/100 g for total oligosaccharides and 0.5 g/100 g, for total FODMAPs which are a criterion to categorize low FODMAP diets. Malting conditions should be optimized to enhance its effectiveness in producing low FODMAP foods. This study highlights the importance of selecting appropriate grain variety and processing techniques that modify FODMAP content in foods that can be used for dietary therapy of gastro-intestinal disorders among vulnerable population.

Enhancing nitrogen use efficiency in agriculture by integrating agronomic practices and genetic advances

Nitrogen is a critical nutrient for plant growth and productivity, but inefficiencies in its use in agriculture present both economic and environmental challenges. Enhancing nitrogen use efficiency (NUE) is essential for promoting sustainable crop production and mitigating the negative impacts of nitrogen loss, such as water pollution and greenhouse gas emissions. This review discusses various strategies aimed at improving NUE, with a focus on agronomic practices, genetic advancements, and integrated management approaches. Traditional agronomic methods, including split nitrogen application and the use of controlled-release fertilizers, are explored alongside precision agriculture techniques, which enable real-time adjustments to nitrogen application based on crop and soil conditions. Advances in genetics and biotechnology, such as conventional breeding, genetic modification, and genome editing, have contributed to the development of crop varieties with improved nitrogen uptake and assimilation. Additionally, the role of beneficial microbes, including nitrogen-fixing bacteria and mycorrhizal fungi, is highlighted as a natural means of enhancing nitrogen availability and reducing reliance on synthetic fertilizers. The review further emphasizes sustainable practices such as legume-based crop rotations, continuous cover cropping, and organic fertilization, which contribute to soil nitrogen enrichment and overall soil health. By combining these agronomic, genetic, and microbial strategies, a holistic nitrogen management approach can be achieved, maximizing crop yields while minimizing environmental impacts. This integrated strategy supports the development of resilient and sustainable agricultural systems, promoting long-term soil fertility and productivity.

Potential of Nano-particles in Mitigating Abiotic Stress in Crops

Climate change, triggered by anthropogenic activities and other inexorable factors, has led to a surge in abiotic stresses, compromising agricultural productivity and exacerbating environmental degradation (Shahzad et al., 2018). Empirical evidence suggests that abiotic stresses significantly impair crop yields, underscoring the need for innovative solutions (Khan et al., 2018). Recent advances in plant sciences have elucidated the complex mechanisms underlying abiotic stress-induced damage to crop plants. Conversely, breakthroughs in plant physiology, genetics, and applied biology have paved the way for the development of stress-tolerant crop varieties. Furthermore, the nascent field of nanotechnology has emerged as a promising tool for enhancing plant resilience to abiotic stresses through the strategic application of nanoparticles (NPs) (Moisala et al., 2003). Studies have demonstrated that NPs can positively impact plant performance under stress conditions (Yadav et al., 2020). Moreover, the use of nano-scale agrochemicals, including nano-formulated pesticides, herbicides, and fertilizers, has garnered significant attention as a potential means of augmenting plant growth and productivity (Abdel Latef et al., 2017).

Within-Field Temporal and Spatial Variability in Crop Productivity for Diverse Crops—A 30-Year Model-Based Assessment

Within-field soil physical and chemical heterogeneity may affect spatio-temporal crop performance. Managing this heterogeneity can contribute to improving resource use and crop productivity. A simulation experiment based on comprehensive soil and crop data collected at the patchCROP landscape laboratory in Tempelberg, Brandenburg, Germany, an area characterized by heterogeneous soil conditions, was carried out to quantify the impact of within-field soil heterogeneities and their interactions with interannual weather variability on crop yield variability in summer and winter crops. Our hypothesis was that crop–soil water holding capacity interactions vary depending on the crop, with some crops being more sensitive to water stress conditions. Daily climate data from 1990 to 2019 were collected from a nearby station, and crop management model inputs were based on the patchCROP management data. A previously validated agroecosystem model was used to simulate crop growth and yield for each soil auger profile over the 30-year period. A total of 49 soil auger profiles were classified based on their plant available soil water capacity (PAWC), and the seasonal rainfall by crop was also classified from lowest to highest. The results revealed that the spatial variability in crop yield was higher than the temporal variability for most crops, except for sunflower. Spatial variability ranged from 17.3% for rapeseed to 45.8% for lupine, while temporal variability ranged from 10.4% for soybean to 36.8% for sunflower. Maize and sunflower showed a significant interaction between soil PAWC and seasonal rainfall, unlike legume crops lupine and soybean. As for winter crops, the interaction was also significant, except for wheat. Grain yield variations tended to be higher in years with low seasonal rainfall, and crop responses under high seasonal rainfall were more consistent across soil water categories. The simulated results can contribute to cropping system design for allocating crops and resources according to soil conditions and predicted seasonal weather conditions.

Integrated metabolomic and transcriptomic analyses revealed the overlapping response mechanisms of banana to cold and drought stress.

Integrated metabolomic and transcriptomic analyses revealed the overlapping response mechanisms of banana to cold and drought stress.

A dual transcriptome analysis reveals accession-specific resistance responses in Lathyrus sativus against Erysiphe pisi.

Lathyrus sativus (grass pea) is a valuable crop for sustainable agriculture, offering dietary benefits and desirable agronomic traits. However, its yield stability is limited by diseases such as powdery mildew caused by Erysiphe pisi. Increasing fungal resistance to pesticides and environmental concerns demand the development of resistant crop varieties. To identify key defense mechanisms and effector genes involved in the Lathyrus sativus-Erysiphe pisi interaction we analyzed four L. sativus accessions exhibiting varying resistance to E. pisi (resistant, partially resistant, partially susceptible, and susceptible) using a dual RNA-Seq experiment across different time points. We observed a host biphasic response, characterized by an initial burst of gene expression, followed by a quiescent phase, and a subsequent wave of intense gene expression. Common L. sativus defense mechanisms included antifungal protein expression, cell wall reinforcement, and reactive oxygen species-mediated defense. These defenses involved respectively Bowman-Birk type proteinase inhibitors, peptidyl-prolyl cis-trans isomerases and mannitol dehydrogenases. The resistant accession specifically activated early reinforcement of structural barriers associated with lignin biosynthesis and the phenylpropanoid pathway, along with sustained chemical defenses (e.g. eugenol synthase 1), epigenetic regulation, and oxidative stress responses thorough peroxidases and heat shock proteins. The partial resistant accession exhibited a front-loaded defense response at early infection stages. Contrastingly, the partially susceptible accession exhibited a weaker baseline defense, with a slower and less robust response targeting pathogen infection. We identified potential E. pisi effectors, including genes involved in cell wall hydrolysis (e.g. mannosidase DCW1), nutrient acquisition (e.g. secreted alpha-glucosidase), and virulence (e.g. SnodProt1), with a higher diversity of effectors identified in the susceptible accession. In conclusion, this study identifies novel targets such as NLRs and effectors, antifungal proteins and genes related to cell wall reinforcement, within the complex Lathyrus sativus-Erysiphe pisi interaction to support future breeding programs aimed at enhancing resistance to E. pisi in L. sativus and related species.

Preliminary Analysis of Quantum Dots as a Marking Technique for Ceratitis capitata

This study evaluates the potential of quantum dots (QDs) as a marking method for Mediterranean fruit flies (Ceratitis capitata) (Medfly) in comparison to traditional fluorescent powder. As a highly destructive pest impacting a wide variety of fruit crops, an effective marking technique is essential for improving the biological understanding and management of Medflies, including control strategies like the Sterile Insect Technique (SIT). Through multiple controlled experiments, we examined the effects of QDs and fluorescent powder markers on Medfly flight ability, marker retention rates, and marker durability and stability under diverse storage conditions. Fluorescent powder demonstrated consistently high reliability across all parameters, whereas QDs showed reduced retention, particularly when applied to pupae, and had a more pronounced negative effect on flight ability. This was illustrated by the field trials, which did not recapture any of the QD-marked flies, highlighting the current limitations in QD application methods. Additionally, fluorescent powders outperformed QDs in both long-term storage conditions and short-term stability tests. These findings indicate that while QDs possess potential as marking agents, further refinement of application techniques is required to achieve comparable efficacy to fluorescent powders in pest management contexts.

Identification of antifungal lipopeptides from Bacillus subtilis Sh-17 targeting Fusarium oxysporum f. sp. lycopersici

BackgroundThis study addresses the critical issue of Fusarium wilt in tomatoes, caused by Fusarium oxysporum f. sp. lycopersici (FOL), a severe fungal pathogen responsible for global yield losses. Conventional control measures, such as resistant crop varieties and chemical fungicides, have limitations due to environmental concerns and the risk of pathogen resistance. As a sustainable alternative, this study aims to explore the biocontrol potential of the bacterial strain Sh-17, focusing on its lipopeptides (LPs) to effectively suppress FOL.ResultsThis study demonstrated the antifungal capability of the Sh-17 strain, obtained from a tomato field, against FOL. Through 16S rDNA gene sequence analysis and phenotypic evaluation, Sh-17 was identified as Bacillus subtilis Sh-17. During the disease control assay using in vitro petri dishes, Sh-17 showed promising plant growth-promoting and disease-control capabilities in seedlings when tomato seeds were inoculated with both Sh-17 and FOL. Subsequently, the lipopeptide extract derived from Sh-17 showed strong antifungal properties in a dose-dependent manner, with complete inhibition of FOL at a concentration of 3500 µg mL−1. Furthermore, it was observed that LPs decreased the amount of ergosterol, which affects the stability and general structure of the plasma membrane. The genomic DNA of Sh-17 was subjected to PCR screening, which revealed the presence of genes responsible for the biosynthesis of antifungal LPs. Furthermore, LC–MS analysis identified distinct LPs, such as surfactins, fengycin, iturins, bacilysin, and bacillomycin derivatives in the crude LPs extract of Sh-17. Moreover, microscopic analyses (fluorescent/TEM) demonstrated morphological abnormalities and even death of the hyphae and spores of the phytopathogen upon its interaction with LPs.ConclusionsB. subtilis Sh-17 exhibits strong antifungal properties against FOL and supports seedlings health by protecting them from pathogen infestation. The LPs produced by Sh-17 inhibit FOL growth in a dose-dependent manner by disrupting the pathogen’s cellular structures and proved to be an effective biocontrol agent against Fusarium wilt in tomatoes.Graphical abstract

The Impact of Climate Change on Agriculture in the Sichuan Basin over the Past 60 Years

Climate change profoundly affects agriculture, particularly in locations such as the Sichuan Basin, a key grain production region in China. This study analyzes the effects of climate change on Sichuan's agriculture over the past 60 years, focusing on temperature and precipitation trends. Results show that rising temperatures and fluctuating rainfall have directly influenced crop growth cycles, yields, and susceptibility to pests and diseases. Moreover, the phenomenon of climate change has exacerbated the risks associated with extreme weather events, leading to significant ecological disruptions and increased production costs. In response to these challenges, the Sichuan government has implemented a series of adaptive strategies, which include the development of advanced irrigation infrastructure, the establishment of comprehensive agricultural insurance programs, and the promotion of the cultivation of crop varieties that are resilient to changing climatic conditions. These strategies have enhanced the resilience and sustainability of agricultural production. This research emphasizes the importance of integrating macro-level policies with farmer-level innovations to ensure stable agricultural yields and food security under changing climatic conditions.

Respons Lingkungan terhadap Perubahan Iklim Keterlibatan Masyarakat Petani Kajian Ilmu Alamiah Dasar dan Islami

This research aims to provide an in-depth understanding of the impact of climate change on agricultural yields and identify solutions and strategies that can be applied to maintain agricultural yields amid this global challenge. This research uses the literature study method, presenting it descriptively by analysing, collecting data and scientific information from various sources including books, journals and documents related to the research, the preparation is carried out to explore the object of research and develop a deeper understanding of climate change. The results of the study that climate change has a significant impact on agricultural yields, due to uncertainty in the pattern of summer and rainy seasons, to deal with these circumstances farmers develop strategies, one of which is the selection of crop varieties that are more resistant to extreme conditions and the application of efficient irrigation technology. The conclusion of this study emphasizes that a deep understanding of farmers' responses to climate change is crucial to formulate a more comprehensive approach to agricultural management. With the implementation of appropriate adaptation strategies, it is expected to improve food security and farmers' welfare in the face of global climate change challenges.

Two reductases complete steroidal glycoalkaloids biosynthesis in potato.

Steroidal glycoalkaloids (SGAs) are specialized metabolites primarily produced by Solanaceae plants such as potatoes and tomatoes. Notably, α-solanine and α-chaconine are recognized as toxic substances in potatoes. While the biosynthetic pathways of SGAs are largely understood, the final steps of α-solanine and α-chaconine biosynthesis remained elusive. In this study, we discovered that two reductase-encoding genes, reductase for potato glycoalkaloid biosynthesis 1 (RPG1) and RPG2, complete SGA biosynthesis in potato. Knockout of both RPG1 and RPG2 in potato hairy roots halted α-solanine production, leading to the accumulation of zwittersolanine. We analyzed the catalytic function of recombinant enzymes and conducted structural determination of the reaction products by nuclear magnetic resonance. As a result, RPG1 converted zwittersolanine to 16-iminiumsolanine, and RPG2 further converted it to α-solanine. RPG2 also transformed zwittersolanine to 22-iminiumsolanine, which RPG1 then converted to α-solanine. Similar processes were observed for α-chaconine synthesis from zwitterchaconine. Due to differences in enzymatic reaction efficiency, the biosynthetic pathway via 16-iminiumsolanine/16-iminiumchaconine was suggested to be predominant in potato. Our results could pave the way for tailoring SGA structures within Solanum plants, enabling the development of Solanum crop varieties with reduced toxicity or enhanced resistance to diseases and pests.